(i) Field of the Invention
The present invention relates to a standard radio signal repeating installation which receives a standard radio signal for transmitting time information, corrects it own time, and transmits the time information to a subsidiary device to thereby correct the time held by the subsidiary device. The present invention also relates to a time information control system using this repeating installation.
(ii) Description of the Related Art
Radio signals containing time information are broadcast throughout the world. For example, in Japan a standard radio is broadcast by Japan""s Ministry of Post and Telecommunications, and a radio correction clocks for receiving this radio signal to correct displayed time are well known.
The transmitted information includes, for example, minute, hour, and day counted from January 1.
In the configuration shown in FIG. 3B, for the transmission of time data, one minute is used as one frame at a rate of one bit per second, and the above-listed information of minute, hour, and day counted from January 1 is encoded within this frame with a BCD code. Moreover, the data to be transmitted includes a P code marker in addition to 0 and 1. This P code exists in several places in one frame and appears at a positive minute (0 second), 9 seconds, 19 seconds, 29 seconds, 39 seconds, 49 seconds, 59 seconds. This P code continuously appears only once at 59 seconds, 0 second in one frame, and this continuously appearing position corresponds to a positive minute position.
Auxiliary equipment of the radio wave correction clock include repeating installations, concerning which a large number of patents have been issued. For example, Japanese Patent Application Laid-Open No. Hei 9-113647 relates to a so-called parentage clock, in which a parent device receives data transmitted from a base station, and then optically transmits the received data to a subsidiary equipment. In this technique the parent or subsidiary device must be placed in a transmission or reception state by switch operation, which is troublesome. Moreover, for a switch to summer time or in other cases when the time information suddenly changes, a user must perform the SW operation, for which they must be aware of the know the changeover period and new time value.
As described above, it is troublesome for the user to place the parent or subsidiary equipment in the transmission or reception state by the SW operation. Another problem is that every time the time data suddenly changes as for daylight savings time, the user must recognize the change and perform the operation. An object of the present invention is to provide a repeating installation and a time control system in which the time data of a subsidiary device can be automatically updated, even during changeover between standard and daylight savings time, referred to in this specification as summer time or ST and winter time or WT.
To attain the above-described object, according to the present invention, there is provided a time information repeating installation comprising receiving means for receiving information including standard time information; timing means for measuring time based on the time information obtained by the receiving means; transmitting means for transmitting, at a predetermined time, the information obtained from the receiving means; and change recognizing means for recognizing a change of said standard time information, wherein said transmitting means performing a transmitting operation based on an output of the change recognizing means at a time different from said predetermined time.
The change recognizing means preferably recognizes changeover advance notice information of standard time information.
It may also be preferable that the transmitting means performs the transmitting operation at said predetermined time and at a time interval corresponding to correction time recognized by said change recognizing means.
It may also be preferable to dispose change period setting means for setting a period in which the transmitting means performs the transmitting operation at the time different from the predetermined time.
The change period of the change period setting means is preferably adjustable.
The change recognizing means for recognizing the change of the standard time information preferably recognizes a changeover of summer time and winter time.
It may further be preferable to provide the time information repeating installation with computing means for computing a difference between the time information obtained by the receiving means and the time measured by the timing means, so that, when the difference outputted from the computing means is greater than or equal to a predetermined value, the transmitting means performs the transmitting operation at the predetermined time and at the time based on the difference.
It may be preferable to dispose the change recognizing means for recognizing the change, so that the computing means operates on receiving the output of the change recognizing means.
The change recognizing means may preferably comprise detecting means for detecting a time change advance notice bit included in the standard time information.
The change recognizing means may also preferably comprise calendar information holding means for holding the present calendar information, changeover day holding means for holding a time information changeover day, and comparing means for comparing the calendar information held by the calendar information holding means and the changeover day holding means.
The above-described time information repeating installation, and a time display for receiving the information outputted at least from the time information repeating installation at the predetermined time may preferably be included.
Moreover, according to the present invention, there is provided a time information control system comprising a time information repeating installation comprising receiving means for receiving information including standard time information, timing means for measuring time based on the time information obtained by the receiving means, and transmitting means for transmitting the information obtained from the receiving means at a predetermined time; and a time display comprising receiving means for receiving the information transmitted from the time information repeating installation at a predetermined time, timing means for measuring the time based on the time information obtained by the receiving means, and change recognizing means for recognizing a change of the standard time information, so that the receiving means of the time display performs a receiving operation based on the output of the change recognizing means at the time different from the predetermined time.
The transmitting means of the time information repeating installation preferably transmits a time change advance notice bit included in the standard time information, and the change recognizing means preferably comprises detecting means for detecting the time change advance notice bit of the standard time information.
The receiving means of the time display may preferably perform reception, even at the predetermined time.
It may also be preferable to dispose change period setting means for setting a period in which the receiving means of the time display performs the reception at a time different from the predetermined time.
The change period of the change period setting means may be adjustable. The change recognizing means may be preferably constituted of calendar information holding means for holding the present calendar information, changeover day holding means for holding a time information changeover day, and comparing means for comparing the calendar information held by both holding means.
It may be preferable that the change recognizing means for recognizing the change of the standard time information be able to recognize the changeover to the summer time and the winter time.
Furthermore, according to the present invention, there is preferably provided a time information repeating installation comprising receiving means for receiving a signal including standard time information; transmitting means for transmitting the time information obtained from the signal to a subsidiary equipment; and control means for controlling transmission and reception timings, such that, when a discontinuous changeover of the standard time information is expected, a reception time is set to the control means at the same time as a predetermined changeover time or a short time after the changeover time, and a transmission time is set to a short time after the reception time.
An interval from the reception time to the transmission time may be preferably set to be shorter than the interval to the next reception time.
It may further be preferable that while the predetermined transmission timing by said control means be normally set to a short time before a positive time, and be changed to a short time after the positive time during detection of advance notice information of said discontinuous changeover.